Publications de Benedikt Steitz

Magnetic, paramagnetic and/or superparamagnetic nanoparticles

Heinrich Hofmann, Alke Fink, Benedikt Steitz, Andrija Finka, Jatuporn Salaklang

The present invention relates to nanoparticles having a mean diameter of < 500nm and comprising, at their surface, a selected material. The nanoparticles are taken up by cells under physiological conditions and can be used to isolate interaction partners o ...

2009

Effect of cell media on polymer coated superparamagnetic iron oxide nanoparticles (SPIONs): Colloidal stability, cytotoxicity, and cellular uptake studies

Heinrich Hofmann, Alke Fink, Benedikt Steitz, Andrija Finka, Jatuporn Salaklang

The influence of the composition of the polymer coated polyvinyl alcohol (PVA), vinyl alcohol/vinyl amine copolymer (A-PVA) and polyethylenimine (PEI) coated superparamagnetic iron oxide nanoparticles (SPIONs) on the colloidal stability, cytotoxicity and c ...

2008

Superparamagnetic Nanoparticles as a Powerful Systems Biology. Characterization Tool in the Physiological Context

Heinrich Hofmann, Alke Fink, Jeffrey Alan Hubbell, Benedikt Steitz, Conlin O'Neil, Marc Moniatte, Andrija Finka, Jatuporn Salaklang

Recently, functionalized superparamagnetic iron oxide nanoparticles (SPIONs) have been utilized for protein separation and therapeutic delivery of DNA and drugs. The development of new methods and tools for the targeting and identification of specific biom ...

Wiley-Blackwell2008

Dielectrophoresis-based particle exchanger for the manipulation and surface functionalization of particles

Heinrich Hofmann, Philippe Renaud, Nicolas Demierre, Raphaël Tornay, Jeffrey Alan Hubbell, Thomas Michael Braschler, Benedikt Steitz, Andrija Finka

We present a microfluidic device where micro- and nanoparticles can be continuously functionalized in flow. This device relies on an element called particle exchanger, which allows for particles to be taken from one medium and exposed to some reagent while ...

2008

Application of pulsed-magnetic field enhances non-viral gene delivery in primary cells from different origins

Heinrich Hofmann, Alke Fink, Benedikt Steitz

Primary cell lines are more difficult to transfect when compared to immortalized/transformed cell lines, and hence new techniques are required to enhance the transfection efficiency in these cells. We isolated and established primary cultures of synoviocyt ...

2008

Optical properties of annealed Mn2+-doped ZnS nanoparticles

Heinrich Hofmann, Alke Fink, Yvonne Axmann, Benedikt Steitz

Cysteine stabilized ZnS and Mn2+-doped ZnS nanoparticles were synthesized by a wet chemical route. Using the ZnS:Mn2+ nanoparticles as seeds, silica-coated ZnS (ZnS@Si) and ZnS:Mn2+ (ZnS:Mn2+@Si) nanocomposites were formed in water by hydrolysis and conden ...

2008

Superparamagnetic iron oxide nanoparticle coupled tissue soldering

Heinrich Hofmann, Alke Fink, Benedikt Steitz

The invention relates to superparamagnetic iron oxide nanoparticles for use in sutureless thermal mediated tissue fusion. The nanoparticles are dispersed in a biocompatible solder material and heated by application of an alternating electromagnetic field. ...

2007

PRODUCTION AND BIOFUNCTIONALIZATION OF MAGNETIC NANOBEADS FOR MAGNETIC SEPARATION OF MESSENGER RNA

Heinrich Hofmann, Alke Fink, Benedikt Steitz

The synthesis of nanosized beads of superparamagnetic iron oxide nanoparticles coated with 3-(aminopropyl)triethoxysilane is reported in this paper. The resulting beads are agglomerates of SPIONs with an open fractal like structure. These beads have been e ...

2007

Superparamagnetic iron oxide binding and uptake as imaged by magnetic resonance is mediated by the integrin receptor Mac-1 (CD11b/CD18): Implications on imaging of atherosclerotic plaques

Heinrich Hofmann, Alke Fink, Benedikt Steitz

Introduction: Superparamagnetic iron oxide nanoparticles (SPIONs) have been successfully used for magnetic resonance imaging (MRI) of atherosclerotic plaques. Endocytosis into monocytes/macrophages has been proposed as the mechanism for SPION uptake, but a ...

2007

Characterization of PEI-coated superparamagnetic iron oxide nanoparticles for transfection: Size distribution, colloidal properties and DNA interaction

Heinrich Hofmann, Alke Fink, Benedikt Steitz

Superparamagnetic iron oxide nanoparticles (SPIONs) were coated with polyethylenimine. Here, we briefly describe the synthesis as well as DNA:PEI:SPION complexes and the characterization of the compounds according to their particle size, zeta-potential, mo ...

2007

Positional Control of Superparamagnetic Iron Oxide Nanoparticles in Silica Beads U

Heinrich Hofmann, Alke Fink, Sandrine Gay, Benedikt Steitz, Franziska Krauss

2007

Fixed bed reactor for solid phase surface derivatization of superparamagnetic nanoparticles

Heinrich Hofmann, Alke Fink, Benedikt Steitz, Andrija Finka, Jatuporn Salaklang

The functionalization of nanoparticles is conditio sine qua non in studies of specific interaction with a biological target. Often, their biological functionality is achieved by covalent binding of bioactive molecules on a preexisting single surface coatin ...

2007

Coating and functionalization of nanoparticles for biomedical applications

Benedikt Steitz

Only with appropriate coatings and coating techniques the use of nanoparticles is possible for biomedical applications. The appropriate choice of the coating material and techniques helps to render the particles biocompatible, colloidally and chemically st ...

EPFL2006

Systemic Distribution and Elimination of Plain and with Cy3.5 Functionalized Poly(vinyl alcohol) Coated Superparamagnetic Maghemite Nanoparticles After Intraarticular Injection in Sheep In Vivo

Heinrich Hofmann, Alke Fink, Benedikt Steitz

PVA coated and fluorescent dye (Cy3.5) functionalized vinyl alcohol/vinyl amine copolymer coated superparamagnetic iron oxide nanoparticles (SPION) were evaluated for systemic distribution and elimination after intraarticular injection in sheep. Observatio ...

2006

Gene Expression in Synovial Membrane Cells After Intraarticular Delivery of Plasmid-Linked Superparamagnetic Iron Oxide Particles—A Preliminary Study in Sheep

Heinrich Hofmann, Alke Fink, Benedikt Steitz

This study evaluated in vivo gene deliver y and subsequent gene expression within cells of the synovium in the presence of static and pulsating magnetic field application following intraar ticular injection of super paramagnetic iron oxide nanopar ticles l ...

2006

Uptake and Biocompatibility of Functionalized Poly(vinylalcohol) Coated Superparamagnetic Maghemite Nanoparticles by Synoviocytes In Vitro

Heinrich Hofmann, Alke Fink, Benedikt Steitz

Superparamagnetic iron oxide nanoparticles (SPION) were coated with either Polyvinyl alcohol (PVA) or Vinyl alcohol/vinyl amine copolymer and further functionalized with the fluorochromes Cy3.5 or Texas Red. A colloidally stable suspension of nanoparticles ...

2006

Enhancement of the efficiency of non-viral gene delivery by application of pulsed magnetic field

Heinrich Hofmann, Alke Fink, Benedikt Steitz

New approaches to increase the efficiency of non-viral gene delivery are still required. Here we report a simple approach that enhances gene delivery using permanent and pulsating magnetic fields. DNA plasmids and novel DNA fragments (PCR products) contain ...

2006

Intraarticular application of superparamagnetic nanoparticles and their uptake by synovial membrane—an experimental study in sheep

Heinrich Hofmann, Mathieu Chastellain, Alke Fink, Benedikt Steitz

A superparamagnetic iron oxide nanoparticle, coated with polyvinyl alcohol, (PVA-SPION) and its fluorescently functionalized analogue (amino-PVA-Cy3.5-SPION) were compared in vivo as proof of principle for future use in magnetic drug targeting in inflammat ...

2005